The present invention relates to a shutoff wedge for a shutoff valve, which is displaceable in a valve housing transverse to a flow direction, carries at its both small sides guiding grooves engaging with guiding projections of the valve housing and in which a row cast iron body is provided with rubber elastic jacket whose sealing face portion lies in the closed position of the valve elastically against seat faces of the valve housing.
In known weak-tight valves, not only relatively thick-walled elastic sealing strand abutting against the housing seat face is rubberized in the region of the sealing faces on the cast iron shutoff wedge, but also the remaining surface of the shutoff wedge is provided at its all sides with a rubber elastic jacket. Thereby the thick sealing face portion is held firm on the shutoff wedge and the shutoff wedge is corrosion protected on its entire surface. The sliding faces of the guide grooves are not rubberized, and thereby they form together with the guiding projections of the valve housing, a relatively friction free sliding guide.
With mounting of such shutoff valves in drinking water conduits it has been recognized that in the iron guiding grooves of the shutoff wedge rust can take place, and therefore again a transition was made to rubberize the sliding faces of the guiding grooves. Such a rubber elastic coating in the guiding grooves of the shutoff wedge possess however poor sliding properties and is subjected to very high wear. Therefore, on the one hand because of the high friction, high shaft forces are necessary, and on the other hand, the wedge guide is worn very fast.